Print "waiting for job termination" at most once.

Print "waiting for job termination" at most once.

This message is useless, annoying, and is the UI equivalent of littering... but
it does explain why your backup command is just sitting there.

Change-Id: Ied49d0bf9f81b0e10804133c6f05814321d80438
Reviewed-on: http://gerrit.openafs.org/6223
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>